Clockwork Princess- Cassandra Clare

Danger and betrayal... Secrets and enchantment... The third and final book in the bestselling Infernal Devices trilogy about the Shadowhunters.

A net of shadows begins to tighten around the Shadowhunters of the London Institute. Mortmain needs one last item to complete his plan. He needs Tessa. But Jem and Will, the boys who lay equal claim to Tessa's heart, will do anything to save her.

“This book had me on an emotional rollercoaster - one minute I'd be happy and excited, the next I'd be crying because of the sad scenes (sad, but beautiful). It didn't take me long to finish!” THE GUARDIAN ONLINE